1. Field of the Invention
The present invention relates to a method of controlling an apparatus for taking out an injection-molded product from an injection mold and the apparatus for carrying out the method.
2. Disclosure of the Prior Art
FIG. 5 is a schematic diagram showing the areas surrounding an injection molding mechanism and an apparatus for taking out a molded product in an injection molding machine.
A female mold 26 of an injection mold 24 is mounted on a fixed platen 23 disposed at the forward end of an injection machine 1, and a male mold 25 is mounted on a movable platen 22 to be driven by a mold-clamping cylinder 21.
An apparatus 3 for taking out an injection-molded product according to the present invention is provided at a position upward of the mold 24.
The apparatus 3 comprises an movable arm 49 having a product holder 42 for holding a molded product 10 by absorption; a servomotor 91 for moving the movable arm 49 in a mold-clamping direction (hereinafter referred to as xe2x80x9cclamping direction servomotor 91xe2x80x9d); and a servomotor 92 for ingress of the product holder 42 between the male mold 25 and the female mold 26 in an open state (hereinafter referred to as xe2x80x9cingress direction servomotor 92xe2x80x9d).
According to the above-mentioned embodiment, the product holder 42 is moved along a locus C shown by an imaginary line in FIG. 5 to take out the molded product 10.
More specifically stated, the product holder 42 laid at a waiting position A1 indicated by a solid line in FIG. 5 is moved in a direction at a right angle to the mold-clamping direction (hereinafter referred to as xe2x80x9cclamping directionxe2x80x9d) by operating the ingress direction servomotor 92. Then the product holder 42 is moved in the clamping direction by operating the clamping direction servomotor 91 before the ingress direction servomotor 92 is stopped. When the clamping direction servomotor 91 commences the operation, the product holder 42 is moved along a curve R and arrives at a holding position A4 at which the product 10 is held (held by the male mold 25). Thereafter a vacuum device (not shown) is operated to hold the product 10 by means of absorption with the product holder 42. Then the product holder 42 is returned along the locus C and the product 10 is released at a specified releasing position to complete the withdrawal of the product 10.
According to this embodiment, when the product holder 42 approaches the product 10 held by the male mold 25, the product holder 42 is moved along the curve R by operating the clamping direction servomotor 91 during the operation of the ingress direction servomotor 92. As a result, the product holder 42 reaches the holding position A4 in the vicinity of the male mold 25 in a shorter time than when the clamping direction servomotor 91 is operated after complete stoppage of the ingress direction servomotor 92 (when the product holder 42 is moved along a L-shaped locus instead of the locus C), whereby the product 10 can be quickly taken out. However, the foregoing conventional embodiment poses problems that a skill is required in adjusting the length of a final linear zone L of the locus C in replacement of the injection mold and that the adjustment of the length is time-consuming.
The foregoing problems will be described in detail.
To obviate or alleviate an error in absorptively holding the product 10 by the product holder 42, the product holder 42 should be moved straight in the clamping direction in the final linear zone L of the locus C.
When the final linear zone L does not exist, especially in the following case, a disadvantage is entailed. Immediately before the product holder 42 at the waiting position A1 arrives at a linear line between the male and female molds 25, 26, the product holder 42 may come into contact with the product 10 on reaching the foremost position in the clamping direction, so that the product holder 42 in contact with the product 10 is moved to the holding position A4, and a force in a moving direction may be exerted on the product holder 42 and then on the product 10, whereby the product 10 may be rendered unstable.
In conventional embodiments of the apparatus 3 for taking out an injection-molded product, the operator actuates an operating device 13 in order to input the length of an initial linear zone S for the linear movement of the product holder 42 from a waiting position A1 to a starting position of curved movement. Thus, the operator actually conducts injection molding operation to visually inspect whether the final linear zone L of the required length is correctly set. If the final linear zone L is found to have an improper length, the operator must re-set the length thereof in the operating device 13. Namely a skill is required in adjusting the length of the final linear zone L.
The foregoing problems are posed by the embodiments of the type wherein the product 10 is absorptively held by the product holder 42. However, the same problems would be encountered by embodiments having a product holder 42 wherein the product 10 is taken out as held between two pinching elements.
An object of the present invention is to provide a method of controlling an apparatus for taking out an injection-molded product, and the apparatus for carrying out the method, the apparatus being capable of taking out a injection-molded product 10 from a mold in an open state while held by a product holder 42 and releasing it at a releasing position, the apparatus comprising: clamping direction driving means for moving a product holder 42 in a clamping direction; and ingress direction driving means for moving the product holder 42 in a direction at a right angle to the clamping direction such that the clamping direction driving means is operated during the operation of the ingress direction driving means and after stoppage thereof, whereby the product holder 42 is moved along a locus C starting from a waiting position A1 via an initial linear zone S, a curve zone R and a final linear zone L to a holding position A4 for holding the product 10, wherein the length of the final linear zone L can be easily changed when the mold is replaced.
To achieve the foregoing object, the present invention provides a method of controlling an apparatus for taking out an injection-molded product, the method comprising the steps of: determining a time required for the movement of the product holder 42 toward a clamping direction from a starting position of movement in the clamping direction by a distance equal to a difference between a length from the waiting position A1 to the holding position A4 in the clamping direction and the length of the final linear zone L; subtracting the above-mentioned time (hereinafter referred to as xe2x80x9ccomplementary timexe2x80x9d) from a time required for the movement of the product holder 42 from the waiting position A1 to a point on a straight line between the male and female molds in an open state (hereinafter referred to as xe2x80x9cingress timexe2x80x9d); and adopting, as the length of the final linear zone S, a linear distance along which the product holder 42 moves from the waiting position A1 toward the point on the linear line for the same period of time as obtained by the subtraction.
The effects of the technical means mentioned above will be described with reference to FIG. 4.
The complementary time is a time required for the product 42 to move from the starting position of movement in the clamping direction along a distance equivalent to a difference (Xxe2x88x92L1) between a distance X in the clamping direction from the waiting position A1 to the holding position A4 on one hand and a distance L1 of the final linear zone L on the other hand. Therefore, when the product holder 42 is moved earlier by the complementary time t2 than the product holder 42 reaches the point on the linear line between the male and female molds in an open state, the product holder 42 is advanced by the distance (Xxe2x88x92L1) in the clamping direction when it arrives at a point on a linear line between the male and female molds. Consequently, the product holder 42 can be moved in a linear direction by a distance L1 set by the operator as the final linear zone L.
An ingress time t1 required for the product holder 42 to move from the waiting position A1 to a point on a linear line between the male and female molds in an open state is determined and the complementary time t2 is subtracted from the ingress time t1. The obtained time is equal to a time for the product holder 42 to move from the waiting position A1 to a starting position A2 of curved movement and corresponds to the starting time ts of curved movement as shown in FIG. 4. When a linear distance S1 is determined along which the product holder 42 moves from the waiting position A1 toward a point on the linear line for the same period of time (until a starting time ts of curved movement comes), the linear distance S1 is the length of the initial linear zone S which is required for assuring that the product holder 42 moves straight by a distance L1 as the final linear zone L.
Consequently, when the molded product 10 is taken out by the apparatus with the linear distance S1 set as the distance of initial linear zone S, the product holder 42 straight moves by the length L1 set as the final linear zone L to reach the holding position A4.
A wide variety of embodiments for the product holders 42 include those capable of holding the product by absorption with a vacuum device, and those in which the product is held between a pair of pinching elements.
The present invention can achieve the following results. As described above, according to the technical means of the present invention, the molded product 10 can be taken out based on the length L1 of the final linear zone L. Consequently, the operator can easily adjust the length of the final linear zone L in replacement of an injection mold compared with conventional embodiments wherein the length of the final linear zone L is visually adjusted while repeatedly setting the length S1 of the initial linear zone S on the operating device 13.
To achieve the foregoing object or similar objects, the present invention further provides a method of controlling an apparatus for taking out an injection-molded product, the method comprising the steps of: determining a length (complementary length) by subtracting the length of a specified final linear zone L from the length in a clamping direction between a waiting position A1 and a holding position A4; determining an ingress time for a product holder 42 to move from a waiting position A1 to a point on a linear line between the male and female molds in an open state; determining a complementary time for the product holder 42 to move in a clamping direction by the complementary length from a starting point of movement in the clamping direction; determining a time for the product holder 42 to commence a curved movement by subtracting the complementary time t2 from the ingress time t1; and measuring a linear length for the product holder 42 to move from the waiting position A1 toward a point on a linear line until the above-determined starting time of curved movement, wherein when the product 10 is taken out, the product holder 42 is moved from the waiting position A1 by the above-mentioned linear distance and then the product holder 42 is moved in the clamping direction.
This embodiment is not limited in respect of the order of the steps of determining the complementary length, the ingress time and the complementary time.
The effects of the technical means mentioned above will be described with reference to FIG. 4.
The operator sets the length L1 of the final linear zone L and puts a control action into operation. Then, there is carried out the step of determining the complementary length (Xxe2x88x92L1), namely the length in the clamping direction over the entire zone of curved movement of the product holder 42, the complementary length (Xxe2x88x92L1) being obtained by subtracting the specified length L1 from the length X in the clamping direction between the waiting position A1 of the product holder 42 and the holding position A4 for holding the product.
Subsequently there is conducted the step of determining the complementary time t2 for the product holder 42 to move in the clamping direction by the complementary length (Xxe2x88x92L1). When the product holder 42 is moved in the clamping direction earlier by the complementary time t2 than the product holder 42 reaches a point between the male and female molds in an open state as described hereinbefore, the product holder 42 is moved straight by the length L1 of the final linear zone.
Thus, the step of determining the ingress time t1 is performed, followed by the step of determining the step of subtracting the complementary time t2 from the ingress time t1, whereby there is determined the time required for the product holder 42 to move from the starting position A1 until the product holder 42 reaches a starting position of curved movement, i.e. the time of commencing the curved movement ts. Thereafter there is measured a linear distance S1 along which the product holder 42 moves from the waiting position A1 toward a point on a linear line between the male and female molds in an open state. The linear distance S1 is the length of the initial linear zone S which is required for assuring the linear movement of product holder 42 along the specified length L1, as described above in respect of the position A1.
In taking out the molded product 10, the product holder 42 is moved in the clamping direction when the product holder 42 has moved from the waiting position A1 by the linear distance S1. Likewise, in withdrawal of the product 10, the product holder 42 is linearly moved by the length L1 determined by the means for determining the length of the final linear zone L to reach the holding position A4.
To achieve the foregoing object, the present invention provides an apparatus for taking out an injection-molded product, which apparatus comprises: means for determining the length of a final linear zone in order to set the length of a final linear zone L; means for calculating a length (complementary length) by subtracting the above-specified length of the final linear zone L from the length in a clamping direction between a waiting position A1 and a holding position A4; means for determining a starting time of curved movement by subtracting the complementary time from an ingress time required for an ingress direction servomotor to rotate at a predetermined speed until the product holder 42 starting from the waiting position A1 reaches a point on a linear line between a male mold and a female mold in an open state, the complementary time being one required for a clamping direction servomotor to rotate at a predetermined speed until the product holder 42 moves in a clamping direction by the complementary length from a starting point of movement in the clamping direction; and means for determining an initial rotation amount of the ingress direction servomotor as measured from the initial stage of operation until the determined starting time of curved movement, wherein in taking out the product 10, the ingress direction servomotor is rotated in the rotation amount determined by the means for determining the initial rotation amount of the servomotor, and then the clamping direction servomotor is actuated.
The effects of the technical means mentioned above will be described with reference to FIG. 4.
First, the operator sets a length L1 of the final linear zone L by the means for determining the length of the final linear zone. Then the apparatus is put into operation to obtain a complementary length (Xxe2x88x92L1) by subtracting the length L1 of the final linear zone L from the length X in the clamping direction between the waiting position A1 of the product holder 42 and the holding position A4 of the product 10.
On the other hand the time for the product holder 42 to reach a curved zone R, i.e. a starting time S1 of curved movement, is determined by the means for determining the starting time of curved movement. The starting time S1 of curved movement is obtained by subtracting the complementary time t2 from the ingress time t1 required for rotating the ingress direction servomotor to move the product holder 42 from the waiting position A1 to a point on a linear line between the male and female molds, the complementary time t2 being a time required for rotating the clamping direction servomotor until the product holder 42 moves by the complementary length (Xxe2x88x92L1).
Next, the ingress direction servomotor is rotated at the specified speed. And the rotation amount of the ingress direction servomotor, which is involved until a starting time S1 of curved movement determined by means for determining the starting time of curved movement, is determined by the means for determining an initial rotation amount of the ingress direction servomotor. This rotation amount is equal to the total rotation amount of the ingress direction servomotor which amount is required for the linear movement of the product holder 42 until a starting time of curved movement. Consequently on rotation of the ingress direction servomotor in said rotation amount, the clamping direction servomotor is actuated so that the product holder 42 commences a curved movement at a suitable time. When the product holder 42 commences the curved movement at this point, and is moved in the clamping direction by the complementary length (Xxe2x88x92L1), the ingress direction servomotor is stopped and thereafter only the clamping direction servomotor is rotated to move the product holder 42 linearly along the above-specified length L1.
In taking out the product 10, the ingress direction servomotor is rotated in the rotation amount obtained by the means for determining the initial rotation amount, and then the clamping direction servomotor is put into operation to start the curved movement of the product holder 42. Subsequently the product holder 42 is moved by the length L1 determined, as stated above, by the means for determining the length L1 of the final linear zone L toward the side of the product 10 until it reaches the holding position A4 of the product 10.
The present invention can achieve the following specific results.
As described above, according to the technical means mentioned above, the operator can directly set the length L1 of the final linear zone L by the means for determining the length L1 of the final linear zone L, and thus there is provided an apparatus for taking out an injection-molded product for achieving the foregoing method of controlling the apparatus.
To achieve the foregoing object, the present invention additionally provides an apparatus for taking out an injection-molded product, the apparatus comprising a timer of ingress time for measuring a time for an ingress direction servomotor to rotate at a specific speed until the product holder 42 moves by an ingress length between a waiting position A1 and a point on a straight line between the male and female molds in an open state, a timer of complementary time for measuring a time for a clamping direction servomotor to rotate at a specific speed until the product holder 42 moves along the complementary length, and means for determining a starting time of curved movement by subtracting the complementary time measured by the timer of complementary time from the operation time of the ingress direction servomotor as measured by the timer of ingress time.
According to the above-mentioned embodiment, the timer of ingress time is adapted to measure a time for the operation of the ingress direction servomotor until the rest of operation, whereby a time t1 required for ingression is determined. The timer of complementary time is adapted to measure a time (complementary time) required for rotation of the clamping direction servomotor until the completion of movement of the product holder 42 by the complementary length (Xxe2x88x92L1). A starting time of curved movement ts can be obtained by subtracting the complementary time t2 as measured by the timer of complementary time from the operation time (the ingress time t1 required for ingression) of the ingress direction servomotor as measured by the timer of ingress time.